Set the temperature to 400℉. Grease a 9x13-inch baking dish, or line it with aluminum foil.
Transfer 3 pounds of cubed russet potatoes to a baking dish. Pour 4 tablespoons of extra virgin olive oil over the top and sprinkle with ½ teaspoon of both salt and pepper. Toss until everything is coated and evenly distributed. Then, cover the dish with aluminum foil.
Move the potatoes to the oven and bake for 30-40 minutes. At that point, remove the foil and cook for another 25 to 30 minutes. The potatoes should be fork-tender. Add or reduce cooking time as needed.
On an ungreased 15x10x1-in. baking pan, bake cubed rolls until toasted, 7-10 minutes.
Fry 5 slices of bacon in a large frying pan over medium-high heat. When finished cooking, drain from oil and let cool slightly before chopping. Put them aside for later.
Add ⅔ cup sour cream, 4 ounces softened cream cheese, 1½ cup grated cheddar cheese, crumbled bacon, celery, and ranch mix in a medium-sized mixing bowl. Combine well.
Place potatoes and rolls into greased baking dish. Scrape the cheese mixture on top of the potatoes/rolls and carefully stir everything together until it’s all evenly distributed. Top with extra ½ cup of cheddar. Return the dish to the oven uncovered, and bake until heated through and cheese has melted.
Remove and cool. Make sure you give it a few minutes to cool before serving.